Shell scripting in macOS – Part 6: User interaction

This article is a continuation of the previous article. We will be taking the previous script and using it to build on the concepts we will learning in this article.

Why would we need to do this?

So far our scripts have run without any communication between the script and any user. In many situations this might be enough. Often times we would need to ask the user for some information before proceeding. This could be for confirmation before performing a certain task, or to customise the script actions as they are being performed.

Ways of interacting with the user

We have a few options to do this.

read utility
GUI pop via AppleScript

Let us look at the read utility first.

Reading from stdin

The read commands captures data entered via stdin. This is typically the terminal prompt from where the user enters the data. This captured value is read into a variable.

#!/bin/bash

read -p " What is your name?": NAME 

echo $NAME

This is a simple example. The user is prompted (on stdout) to enter their name. The user types the name and it is stored in a variable. The contents of the variable are then echoed out to stdout again.

Of course, this assumes the user is manually running the script. Later in this article we will go over how we can automate such scripts with the help of ‘expect’ utility.

Reading from a file

Reading from a file is possible thanks to the read command as well as the loop operations we learnt earlier.

Asking question via GUI

The easiest thing to do would be to prompt the user for information via a GUI popup. This makes the experience a lot better. However, we will need something else for that. We will leverage AppleScript (which is a macOS specific scripting language) to show the popup. This will be invoked from the shell script using osascript.

I will be covering the basics of AppleScript in a later article.

First we will look at how to get the dialog to appear using AppleScript. This requires the use of AppleScript display dialog command.


	display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2

view raw displayDialog.scpt hosted with ❤ by GitHub

This will simply show a popup to the user with a message and 2 buttons. We can customise it further:


	display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns"

view raw displayDialog2.scpt hosted with ❤ by GitHub

This adds a custom icon. If we run this script the user would see something like:

Make sure that the path to the custom icon is what you would want it to be.

If we wanted to find out which button the user has selected then:


	button returned of (display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns")

view raw displayDialog3.scpt hosted with ❤ by GitHub

The button returned of tells us which button was clicked. It also adds a nice title for the popup.

The really nice thing to do would be to somehow run this from terminal. To do that we will use the osascript command. This command needs the AppleScript command to be passed is as a statement.

osascript -e '<AppleScript statement>'

Let us add our command here.

osascript -e 'button returned of (display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns")'

Finally to get this value into a script variable we will use command substitution.

userClicked=$(/usr/bin/osascript -e 'button returned of (display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns")')

We can now echo the variable or use it in a condition check.

Example

Let us update our code to ask the user for names they would like to give for their folder.

Just after the line where we finish checking the 3 positional parameters, add this line.

#4. We can prompt the user to see if they wish to provide folder names themselves. This will override any values provided as arguments.
userClicked=$(/usr/bin/osascript -e 'button returned of (display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns")')

This will first ask the user if they wish to provide the folder names or use the defaults. The response is captured in the shell variable userClicked.

Below that we will put an if check to see what the user has selected.

# if the user decides to provide custom names then go ahead and ask the user via GUI prompts. Otherwise use the values sent as arguments or defaults.	
if [[ $userClicked == "Custom" ]]; then
	
else

fi

If the condition is true we have to show dialog prompts to ask the user for the name. This is going to be similar to our first check. However, this one will also have the ability for the user to enter a value. Add 3 prompts, one for each folder. Also add an echo statement to write to the log file. The if should now look like:

if [[ $userClicked == "Custom" ]]; then
	echo "$(date) The user decided to provide custom names." >> $PATH_TO_LOG
	
	TOOLS_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 1" default answer "Utilities" buttons {"OK"} default button 1 with title "Folder that will hold the utilities" with icon POSIX file "/Users/Shared/Finder.icns")')
	
	REPORTS_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 2" default answer "Tools" buttons {"OK"} default button 1 with title "Folder that will hold the tools" with icon POSIX file "/Users/Shared/Finder.icns")')
	
	HELP_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 3" default answer "Help" buttons {"OK"} default button 1 with title "Folder that will hold the support documents" with icon POSIX file "/Users/Shared/Finder.icns")')
		
	echo "$(date) User provided: $TOOLS_FOLDER $REPORTS_FOLDER $HELP_FOLDER" >> $PATH_TO_LOG
else
	echo "$(date) User decided to use default values: $TOOLS_FOLDER $REPORTS_FOLDER $HELP_FOLDER" >> $PATH_TO_LOG
fi

The script is now ready to accept user input. The completed script should look like:

#!/bin/zsh

#-------------------------------------------------------------------------------------------------
#NAME: Folder creator
#AUTHOR: Arun Patwardhan
#CONTACT: arun@amaranthine.co.in
#DATE: 10th August 2021
#WEBSITE: https://github.com/AmaranthineTech/ShellScripts
#-------------------------------------------------------------------------------------------------

#LEGAL DISCLAIMER --------------------------------------------------------------------------------
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#SOFTWARE.
#-------------------------------------------------------------------------------------------------

#LICENSE/TERMS AND CONDITIONS --------------------------------------------------------------------
#MIT License

#Copyright (c) Amaranthine 2021.

#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:

#The above copyright notice and this permission notice shall be included in all
#copies or substantial portions of the Software.
#-------------------------------------------------------------------------------------------------

#ABOUT -------------------------------------------------------------------------------------------
# fileCreator.zsh
# 1.5
#-------------------------------------------------------------------------------------------------

#DESCRIPTION -------------------------------------------------------------------------------------
# - THis script is intended for creating the custom folders that are required on all corporate computers.
# - Run this script on a new computer or a computer being reassigned to another employee.
# - This script can run on all computers.
#-------------------------------------------------------------------------------------------------

#USAGE -------------------------------------------------------------------------------------------
# - To create folders with default names run the command: ./folderCreator.zsh
# - To define your own folder names: ./folderCreator.zsh <folder1> <folder2> <folder3>
# - Available options : Only the help option is available
# - Getting help : Use the -h or the -help options to get more information. Or you can use the man command to view the man page.
#-------------------------------------------------------------------------------------------------

#WARNING/CAUTION ---------------------------------------------------------------------------------
#******************************************************************************************************************
#******************************************************************************************************************
#******************************************************************************************************************
#******************************************************************************************************************
# This script doesn't perform any validation of the folder names being passed in by the user.
# If the script does not see the -h or the -help options then it will assume that the data being passed in is the name of the folder.
# The user of the script must ensure that the desired folder names are passed in.
#******************************************************************************************************************
#******************************************************************************************************************
#******************************************************************************************************************
#******************************************************************************************************************
#-------------------------------------------------------------------------------------------------

#INSTALLATION ------------------------------------------------------------------------------------
# Instructions for placing the script in the correct place are listed here.
# Location: /Library/Scripts/
# Permissions: rwx r-x r-x
#-------------------------------------------------------------------------------------------------

#REQUIREMENTS ------------------------------------------------------------------------------------
# Shell: /bin/zsh
# OS: macOS Big Sur 11.4 or later
# Dependencies: None
#-------------------------------------------------------------------------------------------------

#HELP/SUPPORT ------------------------------------------------------------------------------------
# You can get help by running the following commands.
# ./folderCreator.zsh -h
# ./folderCreator.zsh -help
# OR
# man folderCreator.zsh
# You can also view the log file for the same at: ~/Library/Logs/folderCreator_log_v1-5.log
#-------------------------------------------------------------------------------------------------

#HISTORY -----------------------------------------------------------------------------------------
# ------------------------------------------------------------------------------------------------
# Version 1.0: Basic script which creates the folders
# Version 1.1: Gives user the ability to specify the folder names at run time.
# Version 1.2: Adds safety checks to the scripts
# Version 1.3: Includes documentation as well as ability to get help.
# Version 1.4: Includes optimisation using for loop
# Version 1.5: Prompts the user in the GUI for names for the different folders.
#-------------------------------------------------------------------------------------------------

#-------------------------------------------------------------------------------------------------
# ------------------------------ SCRIPT STARTS HERE ----------------------------------------------
#-------------------------------------------------------------------------------------------------
#-------------------------------------------------------------------------------------------------
#-------------------------------------------------------------------------------------------------

#These are the default values used for the folder names incase the user doesn't provide any.
TOOLS_FOLDER="Tools"
REPORTS_FOLDER="Reports"
HELP_FOLDER="Help"

#Script version number
VERSION_NUMBER="1.5"

#Command name
COMMAND_NAME="folderCreator.zsh"

#1. Check to see if the user is asking for help. In which case we will have to provide information about the command.
if [[ $1 == "-h" ]] || [[ $1 == "-help" ]]; then
echo "ABOUT
-----
fileCreator_v1-5.zsh
Version $VERSION_NUMBER

NAME
----
$COMMAND_NAME — Folder creation utility SYNOPSIS
$COMMAND_NAME folder names [ verbs ]

DESCRIPTION
-----------
$COMMAND_NAME creates 3 folders in the home folder. In case the folder names are not provided then the command will create folders with default names 'Tools', 'Reports', \"Help\".

There is also the option of getting help via the help verb.
- This script is intended for creating the custom folders that are required on all corporate computers.
- Run this script on a new computer or a computer being reassigned to another employee.
- This script can run on all computers.

VERBS
-----
[ −h −help] Both the options are used to invoke the help documentation.
[ −v −version] Both the options are used to get the version number of the folderCreator command.

REQUIREMENTS
------------
The following are the minimum requirements to get the script running.
Shell:\t\t zsh
OS:\t\t macOS Big Sur 11.4 or later
Dependencies:\t None

INSTALLATION
------------
$COMMAND_NAME can be installed anywhere you wish. However, there are certain locations that are recommended.
Location:\t /Library/Scripts/
Permissions: \t rwxr-xr-x

USAGE
-----
$COMMAND_NAME folder1 folder2 folder3
Will create folders with your own names.

$COMMAND_NAME -h OR $COMMAND_NAME -help
Will invoke the help utility.

$COMMAND_NAME -v OR $COMMAND_NAME -version
will print the version number in stdout.

WARNING/CAUTION
---------------
$COMMAND_NAME does not perform any validation of names. The only options that folderCreator accepts are -h and -help verbs or the -v and
-version verbs. If the script does not see the -h , -help or the -v , -version options then it will assume that the data being passed in is
the name of the folder. The user of the folderCreator command must ensure that the desired folder names are passed in. The user will also be
prompted, via the graphical user interface, if he/she wishes to provide the names for the folders. If yes, then there will be subsequent
prompts asking for the folder names.

EXAMPLES
--------
$COMMAND_NAME Resources Results Assistant
This will create 3 folders Resources , Results , Assistant , in the user’s home folder.

$COMMAND_NAME
This will create 3 folders with the default names

$COMMAND_NAME Apps
This will use the Apps name for the first folder but the default names for the last 2 folders.

NOTE
----
The user will be asked if he/she wishes to provide custom names in all the examples mentioned above. The user's value will always override
whatever is being provided to the script or defaults.

DIAGNOSTICS
-----------
The script produces a log file called ~/Library/Logs/folderCreator_log_v1-x.log
This file is typically located in the user’s home folder log folder. The x represents the version number of $COMMAND_NAME
You can view the logs for each respective version.

EXIT STATUS
-----------
In most situations, $COMMAND_NAME exits 0 on success"
exit 0
fi

echo "$(date) Running script $0 to create folders."
echo ""

TODAY=$(date)
PATH_TO_LOG="$HOME/Library/Logs/folderCreator_log_v1-5.log"

echo "$(date) Starting" >> $PATH_TO_LOG

#2. Check to see if the version number is
if [[ $1 == "-version" ]] || [[ $1 == "-v" ]]; then
echo "Version: $VERSION_NUMBER"
exit 0
fi

#3. The following if statements check to see if the script is receiving any arguments. It then picks those arguments and assigns them to the respective variables for use in the script.
if [[ $1 != "" ]]; then
TOOLS_FOLDER=$1
fi

if [[ $2 != "" ]]; then
REPORTS_FOLDER=$2
fi

if [[ $3 != "" ]]; then
HELP_FOLDER=$3
fi

#4. We can prompt the user to see if they wish to provide folder names themselves. This will override any values provided as arguments.
userClicked=$(/usr/bin/osascript -e 'button returned of (display dialog "Would you like to provide names for the folders or use the defaults instead?" buttons {"Custom", "Default"} default button 2 with icon POSIX file "/System/Library/CoreServices/HelpViewer.app/Contents/Resources/AppIcon.icns")')

# if the user decides to provide custom names then go ahead and ask the user via GUI prompts. Otherwise use the values sent as arguments or defaults.
if [[ $userClicked == "Custom" ]]; then
echo "$(date) The user decided to provide custom names." >> $PATH_TO_LOG

TOOLS_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 1" default answer "Utilities" buttons {"OK"} default button 1 with title "Folder that will hold the utilities" with icon POSIX file "/Users/Shared/Finder.icns")')

REPORTS_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 2" default answer "Tools" buttons {"OK"} default button 1 with title "Folder that will hold the tools" with icon POSIX file "/Users/Shared/Finder.icns")')

HELP_FOLDER=$(/usr/bin/osascript -e 'text returned of (display dialog "Enter the name of folder 3" default answer "Help" buttons {"OK"} default button 1 with title "Folder that will hold the support documents" with icon POSIX file "/Users/Shared/Finder.icns")')

echo "$(date) User provided: $TOOLS_FOLDER $REPORTS_FOLDER $HELP_FOLDER" >> $PATH_TO_LOG
else
echo "$(date) User decided to use default values: $TOOLS_FOLDER $REPORTS_FOLDER $HELP_FOLDER" >> $PATH_TO_LOG
fi

#5. Go to the home folder.
cd $HOME

#6. Check to see if each of the folders exists. If it exists then do not create it. Else create the folder.
echo "$(date) Creating folders: $TOOLS_FOLDER, $REPORTS_FOLDER, $HELP_FOLDER" >> $PATH_TO_LOG

for item in $TOOLS_FOLDER $REPORTS_FOLDER $HELP_FOLDER; do
if [[ -d $item ]]; then
echo "$(date) Not creating $item as it already exists." >> $PATH_TO_LOG
else
echo "$(date) Creating $item" >> $PATH_TO_LOG
mkdir $item
fi

#7. Create the task completion file inside each folder.
echo "$(date) Creating hidden file for $item folder." >> $PATH_TO_LOG
cd $item
#8. Generate the file names based on the folder names.
touch ".$item-FolderCreated"
cd ..
done

echo "$(date) Task completed. Have a nice day!"

#-------------------------------------------------------------------------------------------------
#-------------------------------------------------------------------------------------------------
#-------------------------------------------------------------------------------------------------
# ------------------------------ END OF SCRIPT ---------------------------------------------------

I have also performed some additional cleanup. That has been highlighted. The comments and the help have also been updated to reflect the new changes. I have also moved a couple of the echo statements further up the script. These have also been highlighted.

Video

Download

The completed script can be downloaded from here.

Arun Patwardhan's Blog

Computing Tech Blog

Shell scripting in macOS – Part 6: User interaction

Why would we need to do this?

Ways of interacting with the user

Reading from stdin

Reading from a file

Asking question via GUI

Example

Video

Download

2 thoughts on “Shell scripting in macOS – Part 6: User interaction”

Leave a Reply Cancel reply

Why would we need to do this?

Ways of interacting with the user

Reading from stdin

Reading from a file

Asking question via GUI

Example

Video

Download

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2 thoughts on “Shell scripting in macOS – Part 6: User interaction”

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